A huge field of entrants, stunning supercars and exciting races, the ADAC GT Masters has many impressive, positive attributes. One of the most exciting elements is the mandatory pit stop with driver changeover which must be completed between the 25th and 35th lap. The field will often get a good shake-up up at this stage, because the mandatory stop has many pitfalls in store.

The regulations stipulate a minimum length of time for pit stops, usually 65 seconds. The length of the mandatory pit stop is determined by the length of the pit lane. Lines at the entry and exit to the pits mark the beginning and end of the period of time in question. The clock starts ticking as soon as a driver crosses the first line. A sizeable penalty is incurred if the entire procedure is too short as the car crosses the second line. Drivers stopping for too short a time are put in 'detention' and have to return to the pits to serve their penalty. Race stewards ensure that all drivers stick to the minimum period of time allotted.

However, it is up to drivers and teams to keep an eye on the time for themselves. There is certainly no clock in the car or on the pit wall that automatically counts the time down to keep a check on things. It's all done manually. "We have a button on the steering wheel in our Corvette which we use to start the countdown as soon as we cross the first line," said Callaway driver Dominik Schwager. "We then complete our pit stop as usual: Open door, unbuckle harness, first driver out, second driver in, buckle up. We help each other. The whole process is pretty quick once you're well practised. Were we to set off immediately, then we would be under the minimum period of time allowed, so we wait. At the start of a weekend, we as a team measure the time it takes from where we're located to reach the second line - let's say 15 seconds - while sticking to the speed limit in the pit lane. We therefore try to drive off shortly after the countdown display has indicated 15, and so, as far as possible, allow just a little more than 65 seconds for the whole procedure."

As a rule, the cars never fail to stop for less than the minimum length of time, but there have been exceptions, for example, when Patrick Assenheimer, Dominik Schwager's team-mate, received a drive-through penalty for taking too little time in the second fixture of the second race weekend at the Sachsenring. "Better to be a second over the limit than a tenth under," said Schwager. "A drive-through penalty will totally ruin your race, for sure!"

Déjà vu for Schwager & Assenheimer during the third race weekend at the Lausitzring. More problems with pit stop time management. Schwager: "Patrick started the countdown on entering the pit lane. I took over the wheel and was ready to go. However, apart from the stopwatch in the cockpit, our engineer always counts down the time as well. He counted down on the radio: Nine ... eight ... seven - but his countdown was out of sync with the one in the car. I normally listen to the engineer if there's any doubt, but it turned out afterwards that he was wrong, unfortunately. We lost a place in the race as a result. That obviously shouldn't happen, but we're only human."